The Use of Periods, Question Marks, and Exclamation Marks in Written English

By Heather Marie Kosur

Punctuation marks are a convention of written language that increase the ease of reading. Periods, question marks, and exclamation marks are used in seven basic ways in written English. Also included is a printable reference sheet of the rules for periods, question marks, and exclamation marks.

Periods, Question Marks, and Exclamation Marks to End Sentences

1. Use periods to end most declarative and some imperative sentences. Declarative sentences are statements. Imperative sentences make direct commands, express requests, and grant or deny permission. For example:

The puppy is chewing his rawhide.

Flowers smell lovely.

Please wash your hands.

Use question marks to end interrogative sentences. Interrogative sentences are questions. For example:

Is this sentence a question?

Do you have questions about punctuation marks?

Where is the puppy?

Use exclamation marks to end sentences including imperative and declarative sentences that convey strong emotion. For example:

Periods with Abbreviations

Do not use periods with state or organization abbreviations. For example:

IL (Illinois)

NY (New York)

NASA (National Aeronautics and Space Administration)

Use only one period at the end of a sentence when the last word of the sentence is an abbreviation containing periods. For example:

Workers must arrive at their desks by 9:00 a.m.

My family is from the U.S.

His brother is William J. Smith, Jr.

Periods as Decimal Points

3. Use periods as decimal points to separate integrals from fractional parts of numbers. For example:

37.5

99.99%

$1.25

Periods with Poetry and Play Citations

4. Use periods to separate elements in poetry and play citations. Place periods between books and lines of poems; acts and scenes of prose plays; and acts, scenes, and lines of verse plays. For example: